Methods and systems for multi-fuel engine

Abstract

Methods and systems are provided for adjusting a substitution ratio based on water in a combustion mixture of a multi-fuel engine. In one example, a method includes adjusting a substitution ratio in response to an amount of water provided to a multi-fuel engine configured to combust a first fuel and a second fuel, the second fuel different than the first fuel.

The invention claimed is: 
     
       1. A method, comprising:
 adjusting a substitution ratio in response to an amount of water provided to a multi-fuel engine configured to combust a first fuel and a second fuel, the second fuel different than the first fuel, wherein the first fuel is a liquid fuel and the second fuel is a gaseous fuel, and wherein the amount of water is based on an amount of condensate in an EGR cooler. 
 
     
     
       2. The method of  claim 1 , wherein the first fuel is a carbon-containing fuel and the second fuel is a carbon-free fuel. 
     
     
       3. The method of  claim 2 , wherein the carbon-containing fuel is one or more of diesel, hydrogenation-derived renewable diesel (HDRD), biodiesel, syn-gas, alcohol, gasoline, kerosene, ether, and natural gas. 
     
     
       4. The method of  claim 2 , wherein the carbon-free fuel is one or more of hydrogen and ammonia. 
     
     
       5. A method, comprising:
 adjusting a substitution ratio in response to an amount of water provided to a multi-fuel engine configured to combust a first fuel and a second fuel, the second fuel different than the first fuel, and further comprising adjusting a routing of EGR in response to an amount of water in the EGR. 
 
     
     
       6. The method of  claim 5 , wherein adjusting routing of the EGR comprises providing EGR to the multi-fuel engine via an EGR passage, a donor cylinder, or EGR re-ingestion. 
     
     
       7. The method of  claim 6 , wherein EGR re-ingestion comprises adjusting an exhaust valve timing to overlap with an intake valve opening. 
     
     
       8. A method, comprising:
 adjusting a substitution ratio of a cylinder in response to an amount of water provided to the cylinder, wherein the substitution ratio is based on two or more of diesel, hydrogen, ammonia, and ethanol being included in a combustion mixture; and 
 adjusting the amount of water provided to the cylinder via adjusting a routing of EGR, wherein adjusting the routing of EGR comprises flowing EGR from a donor cylinder to decrease the amount of water provided to the cylinder. 
 
     
     
       9. The method of  claim 8 , wherein adjusting the routing of EGR comprises flowing EGR through an EGR passage to increase the amount of water provided to the cylinder. 
     
     
       10. A method, comprising:
 adjusting a substitution ratio of a cylinder in response to an amount of water provided to the cylinder, wherein the substitution ratio is based on two or more of diesel, hydrogen, ammonia, and ethanol being included in a combustion mixture; and 
 adjusting the amount of water provided to the cylinder via adjusting a routing of EGR, wherein adjusting the routing of EGR comprises re-ingesting EGR via adjusting an exhaust valve timing to decrease the amount of water provided to the cylinder. 
 
     
     
       11. The method of  claim 8 , wherein adjusting the substitution ratio comprising increasing the substitution ratio via decreasing an amount of diesel and increasing an amount of one or more of hydrogen, ammonia, and ethanol in response to the amount of water increasing. 
     
     
       12. The method of  claim 5 , wherein the first fuel is a liquid fuel and the second fuel is a gaseous fuel, and wherein the amount of water is based on an amount of condensate in an EGR cooler.